How is hyperthyroidism diagnosed?
Hyperthyroidism can be suspected in patients with: tremors, excessive sweating, smooth velvety skin, fine hair, rapid heart rate, and an enlarged thyroid gland. There may be puffiness around the eyes and a characteristic stare due to the elevation of the upper eyelids. Advanced symptoms are easily detected, but early symptoms, especially in the elderly, may be quite inconspicuous. In all cases, a blood test is needed to confirm the diagnosis. The main tool for detection is measurement of the blood TSH level. As mentioned earlier, TSH is secreted by the pituitary gland. Although the blood tests mentioned previously can confirm the presence of excessive thyroid hormone, they do not point to a specific cause. If there is obvious involvement of the eyes, a diagnosis of Graves' disease is almost certain. A combination of antibody screening (for Graves' disease) and a thyroid scan using radioactively-labelled iodine (which concentrates in the thyroid gland) can help diagnose the underlying thyroid disease. These investigations are chosen on a case-by-case basis.